Various wearable devices have been developed to protect users while in hazardous environments. For example, self-contained breathing apparatus (SCBA) devices are widely utilized by firefighters and other emergency personnel to supply breathable air, as well as to protect their facial areas from heat, flames, debris, and other harmful elements when working in hazardous environments. In another example, welding masks are worn by welders to protect their facial areas from intense light, heat, sparks, and other harmful elements that may be generated during welding.
In these and other conditions, visible light imaging sensors (e.g., CCD-based or CMOS-based sensors) typically cannot capture useful images of surrounding environments when visibility is compromised. Conventional infrared cameras (e.g., used to capture thermal images) may also be unsuitable, because such cameras are typically too bulky and heavy, and are generally handheld or otherwise positioned external to the user. Also, field of view discrepancies and misalignment issues may occur, between where a user may be looking relative to where the conventional infrared camera is pointed, due to the externally mounted infrared camera (e.g., mounted on the helmet of the user) not being completely aligned and tracking precisely the head movements of the user. Moreover, external housings may be required to protect conventional infrared cameras from hazardous external environments. Such housings may add even further bulk and weight, and thus make conventional infrared cameras even more unsuitable for use in hazardous environments.
In addition, it is often difficult for users to view images while engaged in hazardous environments. For example, certain conventional displays (e.g., LCD screens to present images for a user to view directly and/or through a scope) are often problematic when used in hazardous environments. In this regard, external handheld display screens may be unwieldy and may limit the ability of a user to engage in activities. If provided within a mask of a wearable device, a conventional display may actually obstruct a user's view and may make it difficult for the user to adjust the screen position or to simultaneously view the surrounding external environment. Moreover, the mounting of conventional displays (e.g., screens, scopes, and/or eyepieces) at the outer periphery of a user's mask may adversely shift the center of gravity of the wearable device forward which may encumber and fatigue the user.